add script to return image with old build-string

Author: bgruening

remove-old-builds.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python
+
+# This script is used to create a list of old builds of a package-container.
+# The singularity containers here are to a large degree based on Bioconda packages. Hence, we can have for a package with
+# a specific version, let's call it `mehr-licht:1.2`, multiple containers. For example the `mehr-licht:1.2--r341_0` container.
+# The intention of this script is to return containers with old builds to safe space. To be clear there is still a container
+# with the same version `mehr-licht:1.2`, just build against a newer R/Python/... version.
+
+import os
+import sys
+from collections import defaultdict
+
+image_dict = defaultdict(list)
+image_to_archive = list()
+
+for image in os.listdir(sys.argv[1]):
+    if '--' in image:
+        image_name, image_build_string = image.rsplit('--', 1)
+        if '_' in image_build_string:
+            try:
+                build_string, build_number = image_build_string.rsplit('_', 1)
+                image_dict[image_name].append( (build_string, int(build_number)) )
+            except:
+                # some wired image names, needs to be investigated
+                pass
+
+for k, v in image_dict.items():
+    if not v:
+        continue
+    # We want to have the latest build so we need to sort for the latest build-number.
+    # However, we can have the same build-number multiple-times with a different build-string.
+    # In this case we sort the build-string. This is a bit arbritrary, but should cover hopefully most cases. 
+    v.sort(key=lambda x: (x[1], x[0]))
+    # pop the latest element after sorting. The latest element should be the most recent build, all remaining
+    # images stay in the list and can be archived.
+    v.pop()
+    for build_string, build_number in v:
+        name = f'{k}--{build_string}_{build_number}'
+        if os.path.exists(name):
+            image_to_archive.append(name)
+            print(name)
+        else:
+            sys.exit(f'image "{name}" does not exist')
+
+#do something useful with "image_to_archive"
+